Rails chart in the views

Gemfile

gem ‘gruff’
gem ‘rmagick’

index.erb.html

<%= image_tag url_for(:controller => “alarms”, :action => “show_image”, :id => @alarm.id) %>

mymodelController.rb

def show_image

  require ‘gruff’ 
  @notifications = @alarm.notifications
  @nombre = @alarm.name || “Mi alarma”
  g = Gruff::Line.new
  g.title = @nombre
  g.labels = Hash.new() 
  # g.data = Hash.new()
  misdatos = Array.new()
  counter = 0
  @ notifications.each do |notif|
     g.labels[counter] = notif.fecha.strftime(“%d/%m/%Y”)
     misdatos « notif.price
     counter = counter + 1
  end 
  g.data @nombre, misdatos 
  f = Tempfile.new([ ‘tmp_img’, ‘.png’ ])
  @img2 = g.write(f.path) 
  @img = Magick::Image::from_blob(open(f.path).read)[0]
  @img = @img.to_blob
  send_data @img, :type => ‘image/png’, :disposition => ‘inline’
end

Routes.rb

get ‘alarms/:id/show_image’ => ‘alarms#show_image’ , as: :show_image